Islamic State fighters in Syria have reportedly blown up the ancient ruins of Palmyra, an ancient World Heritage home to renowned Roman-era ruins.

Barry Spielman, whose internet surveillance company, Sixgill, has been tracking Telegram channels since the start of the year, said: “Our intelligence suggests that these threats are to be taken seriously.

“Over the last 12 months, we have seen both official and non-official Isis channels move over to Telegram.

“It’s an encrypted platform, making it a lot safer to communicate without being traced.

“We used to just track the Dark Web and Deep Web but now we are tracking Telegram.”

It comes as people living and working near the future king's school have also raised concerns about security at Thomas’s Battersea after a woman filmed herself walking through the corridors unchallenged.

Sarah Burnett-Moore walked into the £17,600-a-year private school, days before the Duke and Duchess of Cambridge’s four-year-old son started on September 7th.

She said the lack of security at the private schools “astonishing.”

The 54-year-old doctor said: “I could have walked in with an IED and set it to go off.

“I live just 200 metres from the school and myself and lots of neighbours are worried about the security implications of the prince’s presence will make the area a target for attacks.”

Mr Spielman said his firm has uncovered plans by ISIS to arm drones for a possible attack.

He warned: “Now we are seeing explicit threats.

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The Prince appears to be Isis’s latest target

“It seems that as ISIS continues to lose ground in Syria and Iraq, it has stepped up its threats to hit the West.

“This threat to Prince George is chilling.

“We have also seen evidence terrorists are planning a strike at the World Cup in Russia.

“These are very worrying times and it is critical we try to uncover these plots.

“Telegram is where many of them are being hatched as we speak.”

Meanwhile, a British Muslim convert, Jack Letts has been charged with being a member of ISIS after being captured in Syria.

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British spies are heavily monitoring Telegram

Jack Letts, from Oxford, was caught by Kurdish forces in May after fleeing the ISIS stronghold city of Raqqa earlier this year

The son of an Oxford farmer who converted to Islam and travelled to Syria, he has been charged with being a member of ISIS.

Letts - known as ‘Jihadi Jack’ - was captured by Kurdish forces after fleeing Raqqa, which was then the group’s de facto capital, earlier this year.

In a statement given to the BBC, the Democratic Federation of Northern Syria (DFNS) said Letts had been taken to a prison in Qamishli, in north-eastern Syria, on the Turkish border.